Almost ninety five percent of all hydrogen produced globally is derived from fossil fuel sources with the balance produced from renewable sources including the electrolysis of water. This is due to sustainable methods being by order of magnitude, more expensive. Modern water electrolysis technologies rely on the use of membranes or diaphragms to provide a means of separating the produced constituent gases. Alkaline water electrolysers (AWEs) are hindered by the cross-diffusion of gases across the diaphragm, limited current densities, and low operating pressures. AWEs remains a well-developed technology, which employs the use of inexpensive materials of construction, but it is hindered by low operating current densities resulting in the high capital cost of plant due their large sizes. Proton Exchange Membrane electrolysers (PEMs) overcome some of the weaknesses associated with alkaline systems by allowing efficient performance at high current densities, pressurised operation and production of superior gas purities. The aggressive acidic environment dictates the need for scarce and expensive materials for use in the construction of electrode parts and membranes.
The Divergent-Electrode-Flow-Through (DEFTTM) solution incorporates some key advantages from both alkaline and PEM systems. It utilises uninterrupted flow of an alkaline electrolyte through two close proximity circular porous electrodes, with the electrolyte entering where the membrane would have been, resulting in the complete elimination of a membrane. For this configuration, flow is the only requirement for continuous high purity gas separation (99.8 vol% H2 and 99.5 vol% O2 at a flow velocity of 0.075 m.s-1). This is a reliable and unique approach capable of achieving stable current densities as high as 3.5 A.cm-2 at efficient cell potentials employing optimal catalysts. The goal for Hydrox Holdings is to realise the commercialisation of its membraneless alkaline water electrolysis technologies and to continue working towards improving and developing clean energy technologies for the future.